Traditionally there have been proposed and developed various control valves used for a valve timing control device for an internal combustion engine. One such control valve has been disclosed in the following Patent document 1.
Briefly speaking, the control valve is equipped with a cylindrical valve body inserted and arranged in a vane rotor fixed to one axial end of a camshaft from the axial direction, a cylindrical sleeve fixedly connected into the valve body, a spool valve element axially slidably disposed in the sleeve, a valve spring for biasing the spool valve element in one axial direction, and a solenoid part for pushing the spool valve element in the other axial direction against the spring force of the valve spring.
The valve body is formed of a metal material and configured to function as an axially elongated cam bolt. The valve body is comprised of a cylindrical main valve-body part arranged on one end side and a small-diameter, cylindrical male screw-threaded structural part arranged at the other end side and formed integral with the main valve-body part.
The sleeve, the spool valve element, and the valve spring are all disposed inside of the main valve-body part. A male screw is formed on the outer peripheral surface of the top end side of the male screw-threaded structural part.
Also formed in the one axial end of the camshaft is a stepped insertion hole comprised of a large-diameter hole in which the main valve-body part of the valve body is inserted and arranged, and a small-diameter hole in which the male screw-threaded structural part is inserted. A female screw, with which the male screw is threadably engaged, is formed on the inner peripheral surface of the small-diameter hole.
In assembling and installing the vane rotor on the camshaft, the vane rotor can be fixed to the one axial end of the camshaft from the axial direction by tightening the head of the main valve-body part through the use of a predetermined jig, while screwing the male screw of the male screw-threaded structural part of the valve body into the female screw of small-diameter hole.